java简单应用----下拉条的 应用

package zuoye0517;import java.awt.*;import java.awt.event.*;import javax.swing.*;import javax.swing.event.*;public class XIA extends JFrame{private JComboBox lst;private JLabel lbl;private Object cities[]={"","叫哥哥","叫爸爸"};public XIA(){super("dadadadad");Container c=getContentPane();c.setLayout(new FlowLayout());lst=new JComboBox(cities);lst.setMaximumRowCount(4);lbl=new JLabel("请从组合框中选择");c.add(lst);c.add(lbl);lst.addItemListener(new Handler1());setSize(300,150);setVisible(true);}public static void main(String args[]){XIA app=new XIA();app.addWindowListener( new Handler2());}class Handler1 implements ItemListener{public void itemStateChanged(ItemEvent e){lbl.setText("你选中了："+lst.getSelectedItem());}}static class Handler2 extends WindowAdapter{public void windowClosing(WindowEvent e){System.exit(0);}}}

一个简单而容易理解的例子  ，需要注意的是监听设置。